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81.
82.
K. Lívanský 《Folia microbiologica》1982,27(6):455-459
The buffering capacity of solutions of KH2PO4 and NaHCO3 increases with their concentration, the behaviour being describable by mathematical expressions. Solutions of KH2PO4 prepared from tap water exhibit a buffering capacity higher by an order of magnitude than those prepared from distilled water.
However, there is no difference between the buffering capacities of solutions of NaHCO3 prepared from tap and distilled water. Urea and NH4NO3 have almost no effect on the buffering capacities of sol utions. 相似文献
83.
84.
During submerged cultivation ofMycobacterium phlei a mixture of macromolecular compounds ia released into the medium. Concentrated filtrates of cultures of different ages were separated on Sephadex G-25 fine and polyanions were found to predominate in the young culture. During further days of fermentation the proportion of polycations significantly increases. The results are discussed with respect to the regulatory complex of esterases. 相似文献
85.
Petr Svoboda Jan Kopecký Josef Houštěk Zdeněk Drahota 《Biochemical and biophysical research communications》1979,89(3):981-987
Binding studies with [14C]-dicyclohexylcarbodiimide showed the presence of binding sites in the beef-heart mitochondrial membrane at a concentration of 1.8 nmol/mg protein (1.4 sites per cytochrome a+a3). Saturation of these sites correlated with the inhibition of the ATPase activity. The maximum binding capacity could be related with the amount of F1-ATPase in mitochondria from various tissues. 相似文献
86.
J. Plachý 《Folia microbiologica》1979,24(2):191-193
Fermentative preparation ofl-alanine byStreptomyces coelicolor 3–19 was developed under laboratory conditions. In a medium containing glucose, corn-steep and mineral salts, the strain accumulated 9 gl-alanine per litre after four days of cultivation. 相似文献
87.
The population of microorganisms in wheat rhizosphere changed in the presence of the fungus Gaeumannomyces graminis var. tritici causing the take-all of wheat. In the majority of cases when the soil was artificially contaminated by the fungus, both the number of bacteria in the rhizosphere and the bacteria/fungi ratio temporarily increased. At the beginning bacteria growing in the presence of NH4+ predominated, later bacteria utilizing organic N-substances prevailed. Pseudomonas fluorescens and the related species colonized the rhizosphere and the soil to a greater extent in the presence of G. graminis. The wheat rhizosphere with G. graminis was found to contain a higher level of the slime-producing bacterium Agrobacterium spp.; this microorganism occurred on hyphal surfaces (in hyphosphere) of both G. graminis growing in soil and Mucor spp. Changes in microbial populations in the wheat rhizosphere during the first stage of colonization by G. graminis can be partly explained by a simultaneous rhizosphere colonization by microorganisms which accompany this fungus in soil. In the period of increase in the number of bacteria in rhizosphere a temporary stimulation of wheat growth was observed. 相似文献
88.
The synthesis of tRNA was demonstrated in pollen ofNicotiana tabacum L. according to the incorporation of labeled uracil, adenosine and guanosine during 4 h of germination. tRNA was extracted from postribosomal supernatant and purified by polyacrylamide gel electrophoresis. The incorporation of guanosine was about 1.68 times higher than that of adenosine. This finding indicates that the whole tRNA chain is formed in pollen tubes. 相似文献
89.
90.
The level of RNA in pollen is approximately 20 mg g-1 and remains constant during 6 h pollen germinationin vitro also in the presence of 2-thiouracil which stimulates pollen tube elongation. The synthesis of RNA in pollen tubes was investigated according to the incorporation of the label from uracil-2-14C, 2-thiouracil-2-14C, orotic acid-5-3H, fructose-U-14C and from32PO4 3- into RNA fractions separated by methylated albumine kieselguhr chromatography. The distribution of radioactivity on elution profiles was different according to the radioactivity source, however it was not changed by the presence of 2-thiouracil in cultivation medium. 2-Thiouracil incorporates into pollen tube RNA at about 50% the rate of uracil. It inhibited the incorporation of orotic acid, of fructose and of phosphate into all RNA fractions. It is suggested that the analogue inhibits the enzymes involved in RNA synthesis essentially as 2-thiouridine-5’-phosphate. 相似文献